(a) Field of the Invention
The present invention relates to a panel and a liquid crystal display including a panel, and in particular, to a panel including light diffraction layer and a liquid crystal display including the panel.
(b) Description of Related Art
A liquid crystal display (LCD) includes a lower panel provided with thin film transistors (TFTs), etc., an upper panel provided with color filters and a black matrix, etc., and a liquid crystal layer interposed therebetween. A plurality of pixel electrodes and a common electrode are formed on the respective panels or on a single panel and supplied with voltages. The LCD varies the voltages applied to the pixel electrodes and the common electrode to change the orientations of liquid crystal molecules. In this way, the LCD adjust the transmittance of light and displays images.
The liquid crystal material of an LCD has birefringence that the refractive indices in a direction of molecular long axes and in a direction of molecular short axes are different from each other. Due to the birefringence, the refractive index which the light experiences depends on the viewing direction of the LCD, and this differentiates the polarization of an incident light with linear polarization after passing through the liquid crystal. Therefore, the color characteristic and the amount of the light in a slanted direction are different from those in a front direction. In particular, a twisted nematic (TN) LCD suffers severe problems such as the contrast ratio depending on the viewing angle, color shift, gray inversion, etc., due to the variation of the retardation of the light.
A technique for solving these problems is developed, which compensates the phase difference in a specific direction using phase difference compensation film. This technique is to solve the viewing angle problem by compensating the phase deviation of the light generated by the liquid crystal in an opposite manner using the compensation films. Then, the viewing angle is ensured in twisted nematic type LCD using the phase difference compensation films, however, the gray inversion in lower viewing angle, etc., still remains.